This invention relates to contour projectors, and more particularly to an improved method and means for projecting onto the screen of the projector erect and unreversed optical images of both the contour of a workpiece, and the face of the workpiece--i.e., the same surface of the workpiece that is being observed by the operator.
In my U.S. Pat. No. 4,223,986, which is assigned to the same assignee as the present application, I disclosed a contour projector having a surface illuminator (a first light source) that was designed to project either a horizontal or vertical beam of light onto the back or rear surface of a workpiece positioned below and in front of the viewing screen of the projector. With the workpiece in this position the front face or front surface thereof, which can be observed by the operator, is positioned in the path of a second light source referred to as the contour or profile illuminator. This construction causes the contour illuminator to project through a lens system onto the projector screen the outline or contour of the workpiece, at the same time that the illuminated rear surface of the workpiece is also projected through the same lens system onto the viewing screen. As a result, while the contour illuminator in fact presents on the screen an erect and unreversed optical image of the contour of the workpiece, the image projected onto the screen by the surface illuminator is not the same image as would be perceived by an operator gazing at the front surface of the workpiece. On the contrary, the image projected by the surface illuminator is the back side of the workpiece, and hence the reverse of the surface which is being observed by the operator.
It is an object of this invention, therefore, to provide an improved method of projecting onto the screen of a contour projector machine not only an upright and unreversed contour image of a workpiece, but also an upright and unreversed image of the front surface of the workpiece, so that the operator will be observing on the screen the image of the exact surface of the workpiece which her or she observes while standing in front of the machine.
Still another object of this invention is to provide for a contour projector or the like an improved projection system which is designed to project upright and unreversed contour and surface images of a workpiece onto either upright or horizontally disposed screens.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.